1. Field of the Invention
The present invention relates to an installation tool for inserting a helical threaded insert into a tapped hole, and more particularly to an installation tool adapted for helical threaded inserts with different sizes.
2. Description of Related Art
To reinforce the tenacity of a tapped hole, an operator usually inserts a helical threaded insert into the tapped hole. When the tapped hole is made from a relatively softer material such as plastic, wood, or the like, the helical threaded insert is employed and inserted into the tapped hole for avoiding the damage of the tapped hole. Furthermore, most of the tapped holes are often damaged after being screwed over and over again. Thus, the operator usually uses a tapping machine to rebuild the thread structure of the tapped hole. However, the diameter of the rebuilt tapped hole will become too large to fasten a screw. In order to solve this problem, the helical threaded insert is used to be inserted into the rebuilt tapped hole for maintaining a proper size corresponding to the screw.
A conventional threaded insert installation tool includes a tubular body member and a mandrel assembly. The mandrel assembly has a cylindrical rod therein. A handle is connected to the rear end of the mandrel assembly and a recess is formed on the front end of the cylindrical rod. The cylindrical rod can grasp the helical threaded insert with the recess. To rebuild a broken tapped hole, an operator may use a power drill to break the thread structure of the broken tapped hole for enlarging the tapped hole at first. Next, the operator holds the tubular body member with one hand and rotates the handle to push mandrel assembly forward with the other hand so as to force the helical threaded insert into the tapped hole. However, the helical threaded insert cannot match all sizes of the tapped hole.
To solve the aforementioned problem, another conventional threaded insert installation tool is disclosed in U.S. Patent Application No. 2009/0158568. The installation tool has a driving mechanism, a series size of head tubes and the mandrels corresponding to a series of threaded inserts. Since the head tubes and the mandrels share the same driving member, the installation tool can be made by fewer components. However, it's inconvenient to insert the helical threaded insert(s) into the tapped hole because the diameter of the helical threaded insert is usually larger than the diameter of the tapped hole. Thus, the operator must keep rotating the tool and screwing the helical threaded insert until the helical threaded insert is completely fed into the tapped hole.
The present invention has arisen to mitigate and/or obviate the disadvantages of the conventional. Further benefits and advantages of the present invention will become apparent after a careful reading of the detailed description with appropriate reference to the accompanying drawings.